The present invention is primarily related to high-precision tunable oscillators.
In the present specification the oscillator circuit shown at reference numeral 1 in the appended FIGS. 1,2 and 3 as well as the device according to the invention, which generates an electric current having a desired frequency will both be designated by the term "oscillator".
A great number of electric or electronic devices comprise tunable oscillators. As regards certain devices of this kind, such as frequency-modulated continuous wave radars (FM-CW), the performance of the device depends directly on the precision of the frequency generated by the oscillator.
It is known to include in an oscillator a frequency servo loop. Any deviation will then modify the control means of the oscillator so as to provide the desired frequency. Such devices comprising a frequency servo loop allow oscillators to be produced which generate frequencies with a precision of several percent.
In accordance with the present invention the corrections to be made to the control of an oscillator or a frequency servo loop of an oscillator are stored in a memory with a view to improving the frequency precision. Such corrections are mainly required due to the utilization of components the behaviour of which is not of a perfectly linear, and due to the variations with temperature of the behaviour of the components used.
It is a primary object of the invention to provide an oscillator which comprises a memory connected to digital-analog converters and to an oscillator; the memory stores the digitalized voltage values required with a view to obtaining the different desired frequencies.